1. Field of the Invention
The present invention relates, in general, to a suction muffler for compressors, a compressor with the suction muffler, and an apparatus having a refrigerant circulation circuit including the compressor, more particularly, to a suction muffler which is designed to increase compression efficiency and reduce noise, a compressor with the suction muffler, and an apparatus having a refrigerant circulation circuit including the compressor.
2. Description of the Related Art
As well known to those skilled in the art, a refrigerant circulation circuit includes a compressor, a condenser, an expansion unit, and an evaporator. A refrigerant under low pressure is fed into the compressor to be compressed, thus generating the refrigerant under high pressure. The condenser condenses the refrigerant fed from the compressor, and the expansion unit expands the refrigerant fed from the condenser. The refrigerant fed from the expansion unit is evaporated in the evaporator to absorb heat from air around it. In a brief description of a refrigerant circulation cycle, the compressor is a moving part providing power to circulate the refrigerant, whereas the condenser, the expansion unit, and the evaporator are immobile parts constituting a refrigerant circulation passage.
The compressor includes a compressing unit, a motor unit, a casing, a suction pipe and an exhaust pipe. The compressing unit compresses the refrigerant using power transmitted from the motor unit. The compressing unit and the motor unit are hermetically sealed in the casing. The suction pipe guides the refrigerant from an outside to the casing. The refrigerant is discharged through the exhaust pipe to the outside of the compressor.
In this case, the compressing unit includes a cylinder block having a compression chamber. A piston is provided in the compression chamber to compress the refrigerant. A cylinder head seals the compression chamber, and is partitioned into a refrigerant discharge chamber and a refrigerant intake chamber. The compressing unit also has a valve unit. The valve unit is provided between the cylinder block and the cylinder head so as to control an intake of the refrigerant into the compression chamber and a discharge of the refrigerant from the compression chamber after compressing the refrigerant.
Further, the compressor includes a suction muffler to reduce noise generated while the refrigerant is sucked into the compression chamber. The suction muffler is installed between the compression chamber and the suction pipe.
There are several patent applications related to the suction muffler, including Korea Patent Appln. No. 10-1997-0052555, 10-1999-0055955, 10-2000-0024345, 10-2001-0034226, which have been invented by the same inventor as the present invention.
The strokes of exhausting and sucking the refrigerant in the compressor which constitutes the refrigerant circulation circuit, together with the condenser, the expansion unit, and the evaporator, are as follows. That is, at the exhaust stroke, the refrigerant compressed in the compression chamber sequentially passes through the valve unit, the refrigerant discharge chamber, the exhaust pipe, and the suction pipe. Meanwhile, at the suction stroke, the refrigerant is fed into the compression chamber after sequentially passing through the suction pipe, the suction muffler, the refrigerant intake chamber, and the valve unit.
In this case, since the exhaust stroke and the suction stroke are alternately carried out in the compression chamber, the suction pipe, all of the suction muffler, and the refrigerant intake chamber may be affected by a discharge pressure of the refrigerant generated during the exhaust stroke, but the valve unit prevents the refrigerant from flowing into the compression chamber. Thus, the refrigerant flowing to the suction muffler is dispersed around the suction muffler, so density of the refrigerant becomes smaller. When the exhaust stroke switches to the suction stroke in such a state, the refrigerant sucked into the compression chamber has small density relative to a volume thereof, so compression efficiency is poor.
Further, the cylinder head is made of a metal having high heat conductivity, such as aluminum, so a heat transfer may occur between the high-temperature refrigerant inside the refrigerant discharge chamber and the low-temperature refrigerant inside the refrigerant intake chamber. Thus, the refrigerant inside the refrigerant intake chamber absorbing heat from the refrigerant inside the refrigerant discharge chamber is thermally expanded, so a volume thereof is increased. Therefore, the compression efficiency is poor relative to the volume of the refrigerant which is sucked into the compression chamber.
In case of sucking or discharging the refrigerant into or from the compression chamber, an intake valve plate of the valve unit is opened or closed several thousand times per minute, so noise is generated due to mechanical friction. Thus, there have made continuous efforts to reduce the noise generated at the valve unit.